Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden and excels: it discloses that returned hours/prices are only valid with their verification date, identifies official sources (Mérimée, Wikidata) and the reservation.url pass-through behavior. It is transparent about data freshness, which is the main behavioral risk for this kind of reference tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, each earning its place: purpose, freshness/citation caveat, and ticket-link instruction. No filler or repetition, and the most important information (what the tool returns) is front-loaded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a low-complexity get-by-slug tool with two params and no output schema, this is complete: it explains the scope of the return, the conditions under which returned hours/prices can be trusted, and the correct handling of reservation.url. Error/not-found behavior is not described, but that is a minor gap for a retrieval tool of this simplicity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3: slug and lang are already described, including lang's enum/default and slug's origin from search_chateaux. The description adds no input-parameter semantics; reservation.url is an output field, not an invocation parameter.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a precise action and object: 'Renvoie tout ce que nous savons d'un château' and enumerates the content categories (résumé factuel, horaires, tarifs, accessibilité, équipements, coordonnées, sources officielles, date de vérification). This makes it unmistakably a get-full-record tool and separates it from search/list siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives strong post-invocation guidance (cite URL/date when reusing schedules/prices; pass reservation.url through as-is), but it never explicitly says when to choose this over search_chateaux or list_events/itineraires. The intended workflow is implied by 'tout ce que nous savons' and by schema's slug provenance from search_chateaux, but not stated in the description.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.